公开(公告)号：DE69231310T2

公开(公告)日：2001-02-15

申请号：DE69231310

申请日：1992-10-12

Applicant: IBM

Inventor： CRABBE EMMANUEL F ,  HARAME DAVID L ,  MEYERSON BERNARD S ,  PATTON GARY ,  STORK JOHANNES M C

IPC: H01L29/73 ,  H01L21/331 ,  H01L29/165 ,  H01L29/737

Abstract: A heterojunction bipolar transistor having a single-crystal emitter with reduced charge storage and acceptable current gain is described herein. The heterojunction transistor comprises a collector region (604), a base region (606) formed on the collector region, and a single-crystal emitter region (608) grown on the base region (606) by low temperature epitaxy. During the formation of the base region (606), a graded profile of 5-23% germanium is added to the base, as the distance to the collector region (604) decreases, thereby decreasing the base bandgap as it approaches the collector region. Further, during the formation of the emitter region (608), a graded profile of 0-20% germanium is added to the emitter as the distance from the emitter-base junction increases. Thus, the emitter bandgap decreases as it moves farther from the emitter-base junction. The result of the above grading profiles is that the emitter bandgap is narrower at the emitter contact than the base bandgap at the emitter-base junction.

公开(公告)号：DE69231310D1

公开(公告)日：2000-09-07

申请号：DE69231310

申请日：1992-10-12

Applicant: IBM

Inventor： CRABBE EMMANUEL F ,  HARAME DAVID L ,  MEYERSON BERNARD S ,  PATTON GARY ,  STORK JOHANNES M C

IPC: H01L29/73 ,  H01L21/331 ,  H01L29/165 ,  H01L29/737

Abstract: A heterojunction bipolar transistor having a single-crystal emitter with reduced charge storage and acceptable current gain is described herein. The heterojunction transistor comprises a collector region (604), a base region (606) formed on the collector region, and a single-crystal emitter region (608) grown on the base region (606) by low temperature epitaxy. During the formation of the base region (606), a graded profile of 5-23% germanium is added to the base, as the distance to the collector region (604) decreases, thereby decreasing the base bandgap as it approaches the collector region. Further, during the formation of the emitter region (608), a graded profile of 0-20% germanium is added to the emitter as the distance from the emitter-base junction increases. Thus, the emitter bandgap decreases as it moves farther from the emitter-base junction. The result of the above grading profiles is that the emitter bandgap is narrower at the emitter contact than the base bandgap at the emitter-base junction.